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Title:
VERTICAL WIND TURBINE WITH TWO ROTORS (VWT-2126)
Document Type and Number:
WIPO Patent Application WO/2011/017780
Kind Code:
A2
Abstract:
A vertical wind turbine with two rotors is a device that converts the kinetic energy of wind into mechanical energy. A vertical wind turbine with two rotors has a common vertical axis of rotation (1) around which two rotors are rotating, in the process of which one rotor is set inside the other. An internal rotor (2) has specially-designed blades (21) that rotate only in one direction. An external rotor (3) can rotate in the same or the opposite direction of the internal rotor (2). The direction of rotation depends to the shape of the inlet guide vanes (20). The inlet guide vanes (20) are arranged to reduce the impact of harmful torque to a minimum, which increases the efficiency of the kinetic wind energy. The central supporting structure (8) is located within the internal rotor (2). Both rotors lean on the central supporting structure (8).

Inventors:
BILIC JOSIP (BA)
Application Number:
PCT/BA2010/000006
Publication Date:
February 17, 2011
Filing Date:
July 02, 2010
Export Citation:
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Assignee:
BILIC JOSIP (BA)
Domestic Patent References:
WO1991019093A11991-12-12
WO1999054623A11999-10-28
Foreign References:
FR2811720A12002-01-18
FR2541732A11984-08-31
US4236866A1980-12-02
US1586914A1926-06-01
Other References:
None
Download PDF:
Claims:
CLAIMS

1. A vertical wind turbine with two rotors is a device that converts kinetic wind energy into mechanical energy and has a common vertical axis of rotation (1) around which rotate two rotors with an internal rotor (2) located within an external rotor (3), in which the internal rotor (2) rotates only in one direction and the external rotor (3) can rotate in the same or opposite direction of the internal rotor with both rotors leaning on the central supporting structure (8).

2. In a vertical wind turbine with two rotors, according to Claim 1 , the method of

determining the shape of all external rotors (3) with eight to sixteen inlet guide vanes (20) consists of the following steps:

(a) a circle of 360 ° is divided with a selected number of inlet guide vanes (20) to obtain the angle α, which closes the two neighboring inlet guide vanes (20);

(b) a circle is described of diameter D, from center C0 ;

(c) line AiBi is drawn, in the process of which point Ai is in the center C0 and point Bi is on the circle;

(d) line AiBi is rotated around point Bi for the angle γ - a+90 wherein the line AiBi after rotating, occupies the baseline of one inlet guide vane (20) on the external rotor (3);

(e) a line is drawn from point C0 to point Ai wherein the line AjBi and line AiC0 close

angle./?;

(f) a circle of diameter D0 is described from center C0 to point Ai wherein the point Ai lies on the circle of diameter D0 and point Bi lies on circle of diameter D, while tgβ=D,/D0;

(g) line AjBi is multiplied by the selected number of inlet guide vanes (20) and radially

arranged on the circle in the process of which all points of A lie on the

circle of diameter D0 and all points of B lie on the circle of diameter D1

3. A vertical wind turbine with two rotors, according to Claim 2, wherein the inlet guide vanes (20) in cross section is right line, or at one end are convex and at the other end are concave.

4. A vertical wind turbine with two rotors according to Claim 1, wherein the inlet guide vanes (20) on the external rotor (3) are fixed with a removable screw fastening so that they can be installed to close the space around the internal rotor (2) for maintenance.

5. A vertical wind turbine with two rotors, according to Claim 1, wherein the number of blades (21) is determined by the number of inlet guide vanes (20) where the circle of the curve of the blade (21) consists the two neighboring point B;

6. A vertical wind turbine with two rotors, according to Claim 1 wherein the external (3) and the internal rotors (2) have the same number of floors where the blades (21) on the upper floor are turned-rotated around the axis of rotation (1) for a specific angle in relation to the blades (21) on the lower floor of the internal rotor (2).

7. A vertical wind turbine with two rotors, according to Claim 1 wherein the electrical

generators (9) and other ancillary equipment are based in the interior of a central supporting structure (8) where the projected capacity of one device is from 0,8kW to 700OkW.

Description:
VERTICAL WIND TURBINE WITH TWO ROTORS (VWT-2126)

TECHNICAL FIELD

Definition

A vertical wind turbine with two rotors (hereafter: VWT-2126) is a device that converts the kinetic energy of wind into mechanical energy to produce electrical energy. In terms of the International Classification of Patents (ICP), the VWT-2126 belongs to Class F03D.

Technical problem

The increasing use of energy from various sources has caused an increase in CO 2 in the atmosphere, which has resulted in global warming. For this reason, it is necessary to shift to renewable and environmentally clean energy sources. One of these forms is the potential of moving air masses - the wind. The main issue in using wind potential is how to raise the efficiency of kinetic wind energy. A wind turbine must be found that will use the energy of wind that is captured efficiently. Also, it is important to make efficient use of the energy potential in the area where the wind turbines are set up. In addition, these new solutions must satisfy the requirements for security, reliability, ease of maintenance, profitability and the economic feasibility of the investment.

STATE OF THE ART

The basic classifications of wind turbines according to their axis of rotation are:

Wind turbines with a horizontal axis of rotation

These turbines are usually produced with three propeller blades. They move through differential pressure, which creates overpressure on one side of the blade and low pressure on the other side. The aerodynamic shape of the blade is very similar to airplane wings. Such wind turbines could theoretically achieve a coefficient of the use of wind energy of up to 0,59. The actual efficiency is essentially different and very often inversely proportional to wind velocity. As the kinetic energy of wind rises, the efficiency of the turbines falls. For example, with a wind speed of 20 m/s, efficiency falls under to 0,12. The top efficiency of 0,5 was achieved with a wind velocity of 7 m/s. The average efficiency is up to 0,35. In addition to energy inefficiency, the major problem is the static tower and bearings of the propellers. The tower to which the propellers are mounted is attached to a base with a reinforced concrete foundation. The foundation must be specially produced and may weigh up to 1,300 tons for one tower. Statics requires that up to 250 tons of steel be used for the tower and the propeller for each wind turbine (3 MW). In addition to the above robustness, they should not be situated in areas with a turbulent wind flow and in places with a rapidly changing wind direction, which limits their use. If the propeller does not face the direction of the wind, it can cause the demolition of the tower. It cannot be based in inhabited areas because of the noise and the danger of collapse. When building a wind farm, the wind turbines should not be set close to each other, thereby reducing the total use of the energy resources in the area. They cannot be based offshore based like mooring buoys. The shipment of construction parts is carried out by a special transport and the installation is performed with special cranes. Maintenance of the major components is performed at a time when there is no wind, which requires the monitoring of weather conditions. These are only a few of the shortcomings that are pushing the search for new solutions for the more efficient use of wind energy. The new solutions are being sought in wind turbines with a vertical axis of rotation. Wind turbines with a vertical axis of rotation

These wind turbines are well resolved statically. They consist of one rotor and one stator. The rotor rotates around a vertical axis of rotation. In its working position, the blade of the rotor has a high coefficient of airflow resistance, where kinetic pressure is created, and with it the high force that creates useful torque. On the opposite side of working position, the wind strikes the blade, which in this position has a lower coefficient of flow resistance and thus less resistance force that creates harmful torque. The difference between the useful torque moment and adverse torque moment gives the working torque moment. The main

disadvantage of turbine with vertical axis of rotation is its low energy efficiency because of the harmful effects of the adverse torque moment. The goal for achieving greater use kinetic energy from the wind is concentrated on the design of blades that will have a higher coefficient of aerodynamic resistance on one side and a lower coefficient on the other side in order to reduce the harmful effects of the adverse torque moment. Also, to prevent adverse torque moment, there are stators whose inlet guide vanes are guided by direction of wind into the working direction and on the other side protect the rotor from the occurrence of adverse torque moment. The resistance of the inlet guide vane reduces the coefficient of the use of wind energy. Turbulence and sudden changes in wind direction have a negligible effect on the static stability of these wind turbines.

SUMMARY OF THE INVENTION

Two rotors are installed which rotate around a common vertical axis, thus creating a higher swept area of wind than wind turbines with a vertical axis of rotation.

With the special shape of the external and internal rotors, the effects of the adverse torque moment are minimized, so the coefficient of the use of kinetic wind energy is increased. At the transmutation of kinetic wind energy into mechanical energy, VWT-2126 achieves a greater theoretical use of kinetic energy than the current one, which is 59%. With regard to the fact that on current devices the actual average efficiency is two times lower than the theoretical one, it is necessary to determine the actual efficiency of kinetic wind energy on VWT-2126 by measurement.

The inlet guide vanes on external rotor direct airflow perpendicular to the internal rotor blades. Regardless of the direction from which outside air enters the inlet guide vanes of the external rotor, the vector of wind velocity at the inlet to the internal rotor is perpendicular to tangent line of recess blades on the internal rotor. Thus, the VWT-2126 can well withstand gusts of wind from different directions simultaneously, and it is not necessary to turn parts of the VWT-2126 in the direction of the wind as with wind turbines with a horizontal axis of rotation.

Since the inlet guide vanes of the external rotor increase the airflow velocity, greater use of the kinetic wind energy is possible with lower wind velocity. This specific quality of the VWT-2126 could decrease the limit of justifiability of investment below 5 m/s of average annual wind velocity.

The electrical generator is installed directly on drive shaft of the rotor or on the shaft with conjugated pair of gears. Moving resistance is lower because it is not necessary to install a gearbox as on previous wind turbines.

The usable area on which the wind farm of VWT-2126 is situated is larger than for wind turbines with a horizontal axis of rotation. Translational airflow is present by an external air inlet in the VWT-2126 and by outflow from VWT-2126, which increases usefulness of the area. For example, if we consider that interspaces (LQ) between two adjoining VWT-2126 is L D = 1, 9 D, then on the transverse longitude wind flow of 1 km, it can be based 1000:2, 9 D pieces. For an altitude of H=50m and a transverse longitude wind flow of 1 km the top of installed capacity on that area is: P sw = 4700 v w 3 up to 5500 v w 3 (W) (V w = wind velocity). For v w =15m/s the power exceeds P= 16, 5 up to 18, 5 MW. It means that six wind turbines with a horizontal rotation axis of 3MW at a distance of 166m should be installed and this cannot be permitted because the space needs to be at least 300-40Om so that the operation of one wind turbine does not disturb the operations of the other wind turbines. A wind turbine with a horizontal axis of rotation of 3MW has a height extending to 135 and 150 m. For the VWT- 2126, with a height of 100m from its base, the calculated capacity is P sw : =9200v w 3 to

11000v w 3 (W). In this calculation coefficients of airflow resistance are assumed. Real coefficients should be determined by measurements on three different sizes of VWT-2126.

The maintenance of the VWT-2126 is simple and less expensive because it does not require special conditions and the use of additional tools and equipment, such as cranes. There is constant, safe, and quick access to equipment that is connected to the drive shaft. The change of load-bearing rollers is possible even with a wind velocity of 6m/s. The inlet guide vanes on external rotor are fixed with separable screw fastenings so they can be installed in order to close the space around internal rotor. Then the repairs or maintenance can be performed when needed, regardless of wind speed and other weather conditions.

The consumption of materials for building the foundation on land is less than 65% per MW of installed capacity (for H=2D) compared to a windmill with a horizontal axis of rotation. The ratio of height (H) and diameter (D) range from H=2D to H=5D for a hard base, while the offshore range is from D=H to D=3H. The selection of type of foundation and the diameter depends on the measured kinetic energy of wind and the base upon on which it is placed.

The lattice structure of the VWT-2126 reduces the consumption of steel by 25-40% per MW of installed capacity (depending on the gusts for which it is designed).

The structural engineering of the VWT-2126 is more stable and resistant to stormy gusts and to the devastating effects of earthquakes than wind turbines with a horizontal axis of rotation.

The VWT-2126 is more suitable as an off-shore installation than current types because it has negligible torsion of the lattice structure on which it is formed. The wide base of footpads on the foundation permits the construction of a VWT-2126 with greater power:

• Off-shore, which is placed on three/four pillars fixed on the sea floor.

• Off-shore with buoys, in which it is fixed to sea floor with four girders and secured with balancing weights,

• On ships and other vessels.

The design of a VWT-2126 with different capacities is simpler because:

• The ratio of the external and the internal diameter of the rotors, the ratio of size of inlet guide vanes and the blades on the internal rotor always result in a constant value.

• The ratio of peripheral velocity of both rotors gives the same value.

If the VWT-2126 is based on a hard base, the existing installed capacity could be increased by building new floors in height. This should be anticipated when building the foundations. Height and width - the VWT-2126 is fixed so that its structure can be illuminated at night for the safety of aircraft, which now is not the case.

The VWT-2126 is an architecturally suitable for urban areas. The wide base and lightweight construction provide an option for installation on the flat roofs of buildings, the only question is that of the noise and vibration that it creates. The level of noise and vibration is still unknown, therefore measurements should be made of several different sizes of VWT-2126 and at different wind speeds. It will then be possible to determine the size of VWT-2126 that is suitable for construction in urban areas.

DESCRIPTION OF THE DRAWINGS

The drawings enclosed with patent application are made on nine sheets A4 format.

The figure is labeled with letters (Fig._) and with one number.

The positions on the figure are labeled with a number. Example: 8 in the drawings means that within the text position 8 is depicted as (8).

The list of figure and positions:

Fig.l shows transversal cross-section of two rotors where the shape of the external and the internal rotor is seen as the swept air. Positions: inlet guide vanes on external rotor (20); blades on internal rotor (21).

Fig.2 shows the longitudinal section of the two rotors where the arrangement of the positions mentioned in the description is shown: vertical axis of rotation (1); internal rotor (2); external rotor (3); lower horizontal layer (4); layer between two floors on external rotor (5); upper horizontal layer (6); layer between two floors on internal rotor (7); central supporting structure (8); electrical generator inside the central supporting structure (9);

Fig.3, Fig.4, Fig.5 and Fig.6 show the mode of determining shape of external rotor (3).

Fig.7, Fig.8 and Fig.9 show the mode of determining shape of inlet guide vane (20).

Fig.10, Fig.l 1 and Fig.12 show the mode of determining shape of internal rotor (2)

Fig.13 shows the mode of closing the space around external rotor (3) with inlet guide vanes

(20).

Fig.14, Fig.15 and Fig.16 show the mode of blade rotation on one floor of internal rotor (2) in regard to next floor

Fig.17 shows the installation mode of VWT-2126 on hard base.

Position: foundation (10)

Fig.18 and Fig.19 show the installation mode of VWT-2126 on soft base or offshore.

Positions: top frame (11); bottom frame (12); upper leaning surface (13); bottom leaning surface (14); electrical generator on the top (19);

Fig. 20 shows the installation mode of VWT-2126 off-shore with buoys.

Positions: buoys (15); balancing weight (16); lashing for fix to the sea floor (17); external girders with hard connection for stability (18).

TECHNICAL DESCRIPTION

The VWT-2126 has a common vertical axis of rotation (1) around which two rotors rotate, where one rotor is inside the other. The internal rotor (2) rotates in one direction. The external rotor (3) could rotate in both directions. The coefficient of aerodynamic resistance of the inlet guide vanes determines the direction of rotation of the external rotor (3) (Fig.l). The swept area (A st ) equals the product of multiplication of the diameter of the external rotor (3) and its height (A st =D o x H). The rotation axis (1) divides swept area into two parts: left (A s ,) and right (A sr ) (Fig.1).

The external and internal rotors have the same number of floors, of which there should be at least two. The floor space is bounded by the lower horizontal layer (4) and the upper horizontal layer (6). The horizontal layer of one floor (5) on the external rotor (3) and the horizontal layer (7) of one floor on the. internal rotor (2) are at the same level.

The external rotor (3) sweeps wind which flows from both sides of the rotation axis (1). The direction of rotation depends on the number and shape of the inlet guide vanes (20). The inlet guide vanes (20) from the left side of the rotation axis (1) intake air to rotation flow (vortex) that strikes the blades (21) under the perpendicular (Fig.l AsI). The wind velocity (vi) that strikes the blades (21) is higher than the inlet wind velocity (v 0 ) on the VWT-2126. The acceleration coefficient of wind depends on the size of the VWT-2126, surface roughness and the recess of the vanes (20). It can achieve a value of 2,1.

The shape and arrangement of the vanes (20) reduce the effects of harmful torque to a minimum so that the theoretical efficiency of kinetic wind energy is higher than the current 59%. Airflow resistances in the VWT-2126 reduce efficiency of kinetic wind energy. A small VWT-2126 has higher airflow resistances and they are less efficient, while with the larger VWT-2126 the efficiency of kinetic wind energy increases.

The inlet guide vanes (20) are fixed with a separable connection so that they can be set to close the space around internal rotor (2) (Fig.13). Repair or maintenance can be done as needed, regardless of wind speed and other weather conditions. Closing is made in a way that the external rotor (3) is fixed on the central supporting structure (8), first, to keep it from rotating. The internal fastening of the inlet guide vanes (20) is released on one floor and they turn around the external fastening in the direction of negative angle. Closing is made on one floor after another.

The internal rotor (2) uses the kinetic energy of the wind from the left side of the axis of rotation (1) (Fig.lA s i) and rotates in the direction of positive angle. Force acting on the focus of impact in the internal blade (21) creates a positive torque. The construction of the blades (21) prevents the waste of the air after striking the blade (21) and holds it in the area around the blade (21), which lessens the impact of the following air mass, reducing vibration.

The blades (21) on the upper floor are turned-rotated around a rotation axis (1) to a specific angle in relation to blades (21) on the lower floor. The angle of the turn is given when the angle 60° is divided with number of floors (60°: FN). Figure 14 shows the shape of the two floors on the internal rotor (2) so that the angle of turn should be 30° (Fig.15) and (Fig.16).

If the rotors rotate in opposite directions, then on the shaft of one rotor a pair of conjugated gears is installed that changes the direction of rotation of that rotor. In that way we get the same direction of rotation on the shaft of the internal rotor (2) and the shaft of the external rotor (3). The mode and place of installing the pair of conjugated gears depends on the size of VWT-2126 and the type of electrical generator.

The bearings of both rotors rest on the central supporting structure (8). The line of rotation axis contains point C 0 (Fig.l) and it intersects level of bearings of both rotors under perpendicular. At the top of the central supporting structure (8) is upper bearing of both rotors. For a VWT-2126 of less capacity, a center- line bearing is installed (to the center of the rotation axis). For a VWT-2126 of higher capacity in addition to the center-line bearing set are still load-bearing rollers. Bearings are located in the center axis of rotation and the load-bearing rollers are arranged radially around the central supporting structure (8).

At the bottom of each rotor, there are bearings that are made with load-bearing rollers. The load-bearing rollers rest on central supporting structure (8).

This method of bearings on the end of both rotors makes the VWT-2126 stable in all working conditions. The bearing mode depends on the size of the VWT-2126.

Maximal projected capacity of one device is from 0, 8 kW to 7,000 kW.

Determining the shape of external rotor:

Determining the basic shape of external rotor (3) with twelve inlet guide vanes (20):

• A circle of 360 is divided with a selected number of inlet guide vanes (20) to obtain the angle α which closes two neighboring inlet guide vanes (20) (for the twelve inlet guide vanes (20) angle α = 30°).

• The circle is described with a diameter Dj from center C 0.

• Line AiB 1 is drawn, in the process point Aj is in the center C 0 and point Bi is on the circle.

• The angle of rotation should be determined: (360/12)+90=120

• Line AiBi is rotated around point Bi for 120°.

• A line is drawn from point C 0 to point Ai

• A circle of diameter D 0 is described from center C 0 to point Ai

• The line A] Bi and the line Ai C 0 close the angle β=30°(Fig.3).

• Point Ai lies on the circle of diameter D 0 and point Bi lies on circle of diameter Dj while .

• The point Bi 2 should lie on the line AiC 0 (Fig.4).

• Twelve lines AB are arranged radially on the circle. Two neighboring lines close the angle α=30°. (Fig.4).

• For the selected twelve inlet guide vane (20) α=β (Fig.4). If the number of the inlet guide vanes (20) is not twelve, then α≠β (Fig. 5) and (Fig.6).

• Each line AB is the baseline to one inlet guide vane (20) of the external rotor (3).

• In that way the external rotor (3) has twelve inlet guide vanes (20), which are arranged radially around the whole circle.

The same method to determine the shape of the external rotor is used for all external rotors (3) with 8 to 16 inlet guide vanes (20) and consists of the following steps:

(a) A circle of 360 is divided with the selected number of inlet guide vanes (20) to obtain the angle α which closes two neighboring inlet guide vanes (20) within nine vanes (20) angle α = 40 °, for ten vanes (20) angle α = 36 °, for eleven vanes (20) angle α =

32.7 °, for twelve vanes (20) angle α = 30 °, for 13 vanes (20) angle α = 27.7 °, for 14 vanes (20) angle α = 25, 7 °, for 15 vanes (20) angle α = 24 °;

(b) A circle is described with a diameter D; from center C 0. ;

(c) Line AiBi is drawn, in the process point Ai is in the center C 0 and point Bi is on the circle;

(d) Line AiBi is rotated around point Bi for the angle γ = a+90 wherein the line AiBj after rotating occupies the baseline of one inlet guide vane (20) on the external rotor (3);

(e) A line is drawn from point C 0 to point Ai wherein the line AiBi and line A]C 0 close angle^ within the angle β= 25° is for a nine inlet guide vane, for a twelve inlet guide vane ^J = 30°' for a fifteen inlet guide vaney? = 33°(Fig.5) and (Fig.6); (f) A circle of diameter D 0 is described from center C 0 to point A 1 wherein point A) lies on the circle of diameter D 0 and point Bi lies on circle of diameter D 1 while tgβ=D,/D 0 ;

(g) The line AiBj is multiplied with a selected number of inlet guide vanes (20) and radially arranged on the circle in the process of which all points of A lie on the

circle of diameter D 0 and all points of B lie on the circle of diameter D,

If the external rotor (3) has less than 12 inlet guide vanes (20), then the efficiency of kinetic wind energy on the internal rotor (2) decreases, while the efficiency of kinetic wind energy on the external rotor (3) increases.

If the external rotor (3) has more than 12 inlet guide vanes (20) then the efficiency of kinetic wind energy of the internal rotor (2) increases while the efficiency of kinetic wind energy of the external rotor(3) decreases.

The ratio of rotation of the external and internal rotors depends on the number of inlet guide vanes (20).

The basic form of the external rotor (3) with nine inlet guide vanes (20) is shown on Fig.5.

The basic form of the external rotor (3) with fifteen inlet guide vanes (20) is shown on Fig.6.

Determining the shape of the inlet guide vane (20):

Determining the basic shape of the inlet guide vanes (20) if the external rotor (3) rotates in the direction of positive angle:

• The shape of the inlet guide vanes (20) is formed around the line A 1 B 1 .

• The points A 1 and C 0 are connected with the line ,

• A circle with diameter D c which has point Ai is drawn. The intersection of the circle and the line A)Bi of that circle and the line A]Co give symmetrical circle parts (Fig.7)

• The curve of the circle with diameter Ri the point Bi is connected with the circle D c at the point of tangent on the circle Ti so that the curve of the circle crosses the line AiB 1 .

• The basic shape of the inlet guide vane (20) is a curve that consists of curve BiT] and the curve TiAi (Fig.8)

Determining the basic shape of the inlet guide vanes (20) if the external rotor (3) rotates in the direction of negative angle:

• The shape of the inlet guide vanes (20) forms around the line A]Bi.

• The points Ai and C 0 are connected with the line

• The circle with diameter D c which has the point Ai is drawn. The cross of circle and the line AiBi of that circle and the line AiC 0 give symmetrical circle parts (Fig.7)

• The curve of circle with diameter: R 2 the point Bi is connected with the circle D c at the point of tangent on the circle T 2 so that the curve of the circle crosses the line AiBi.

• The basic shape of the inlet guide vane (20) is a curve that consists of curve BiT 2 and the curve T 2 Ai (Fig.9)

If the diameter of circle D c is calculated according to the formula: D c =D t ,tgα regardless of the number of inlet guide vanes (20), then for eight inlet guide vanes (20): tgα=l so that D c =D b . This means that it is not possible to make the external rotor (3) using the above described method if it has less than 8 inlet guide vanes (20).

Determining the shape of the internal rotor (2) (fig.10):

Determining the number of blades (21) if the external rotor (3) has twelve inlet guide vanes (20): Theoretical diameter D 1 - of circle of the internal rotor (2) on which six blades (21) are installed equals D 1 = D 0 UgR.

The construction of the external rotor (3) converts linear and stationary airflow on the twelve inlet guide vanes (20) to one rotation flow in the process of which the strongest intensity is on diameter D g =D o sin β and the swept angle of 60° so that on the internal rotor (2) six blades (21) are selected which mutually close the angle of 60° (Fig.10).

Determining the basic shape of the blade (21):

The basic shape of internal rotor (2) depends on the basic shape of the external rotor (3)

• Points Bi and B 1 ] are connected with a line.

• Points B 2 and Bi 2 are connected with a line.

• The center of circle Ci is place at the intersection of line B]Bn and line B 2 Bj 2.

• From the center of circle Ci another circle D b is made that contains points Bi and B 12

(Fig.l l);

• Points C 0 and C 1 are connected with a line.

• Point C 2 is placed at the intersection of line C 0 Ci and circle D b

• The blade (21) that is recessed along circle D b has two final points. One final point is C 2 point Bi is other final point. Line BiCi with line CiC 0 closes the angle of 105° (Fig.l 1).

• To prevent the scattering of mass toward inside rather than keeping it inside circle diameter D g , the space must be closed . It closes so that point C 2 is joined with other final point of the next blade (21) that lies on circle D; (Fig.12).

• The basic shape of blade (21) consists of a segment of circle D b that closes the angle of 105° to point C 2 and the line from C 2 to the other final point of the next blade (21) (Fig.12).

• Six blades (21) of this shape are arranged on the whole circle giving the basic shape of the internal rotor (2) (Fig.12).

Determining the basic shapes of the blades (21) for all external rotors (3) with eight to sixteen inlet guide vanes (20) is the same.

Mechanical energy is converted into electricity through an electrical generator. The electrical generator is installed on two ways.

One electrical generator is installed on the external rotor (3) and another electrical generator on the internal rotor (2). Since the external rotor (3) has higher torque than the internal rotor (2), the installed generator could also act to regulate the rotation of the external rotor (3).

One electrical generator (9) is installed that receives torque from both rotors. If the rotors rotate in opposite directions then a pair of conjugated gears is installed on the drive shaft of one rotor to adjust the direction of rotation with the other rotor. When one generator (9) is used, then the ratio of the rotation of the internal rotor (n;) and the rotation of the external rotor (ri o ) is fixed. When the rotors rotate in the same direction, the theoretical ratio of rotation is: nj/no≥l/tgβ>l,732. Measurements must be made to ensure that the ratio of rotation has the peak efficiency of kinetic energy because airflow resistances are different for different sizes of the VWT-2126.

The ratio of rotation (nj/n 0 ) varies from 1,732 to 2,828, depending on the size of VWT-2126 and radius of the camber on the external rotor (3).

Installation mode of the vwt-2126:

On a hard base (Fig.17) The central supporting structure (8) is installed vertically on a prepared foundation (10). This foundation can be made in complete from reinforced concrete or from a combination of reinforced concrete in the ground and steel construction above the ground. The central supporting structure (8) on which the external rotor (3) and the internal rotor (2) are installed is based inside the internal rotor (2). For a VWT-2126 with less capacity it could be tubular, while for a VWT-2126 with higher capacity a carrier is made as lattice structure. The electrical generators (9) and other ancillary equipment are based in the interior of the central supporting structure (8).

On a soft base or off-shore with a supporting frame-lattice structure (Fig.19)

A frame-lattice structure is built around the external rotor (3). It consists of a top frame (11) and a bottom frame (12). The top frame (11) has four external girders connected by wires to the upper leaning surface (13) and the bottom leaning surface (14). Figure 18 shows a ground-plan of the connection of the top frame (11) with the top leaning surface (13).

The central supporting structure (8) leans on the bottom leaning surface (14). On top of the central supporting structure (8) is the upper bearing of the internal rotor (2). On top of the leaning surface (13) is the upper bearing of the external rotor (3). On top of the leaning surface (13) is the electrical generator (19) and other ancillary equipment.

Below the bottom leaning surface (14) is the bottom frame-lattice structure (12).

Off-shore with buoys (Fig.20)

The frame-lattice structure is built around external rotor (3). It consists of a top frame (11) and buoys (15). The top frame-lattice structure has four external girders connected to the upper leaning surface (13) and the bottom leaning surface (14). The central supporting structure (8) leans on the lower leaning surface (14). On the top of the central supporting structure (8) is the upper bearing of the internal rotor (2). On the upper leaning surface (13) is the electrical generator (19) and other ancillary equipment.

Four hydrodynamically shaped buoys (15) are installed below the bottom leaning surface (14). The lower round part of the buoy is set at a depth where waves do not affect it. The upper portion of the buoy is designed to reduce the impacts of waves. The buoys (15) can be rotated around the axis on which they are based so that they can adjust to all of the directions of the force of wave impacts. Below the buoys (15), four external girders are interconnected with a hard connection for stability (18). At the bottom of each of the external girders is a lashing the other end of which is fixed to the sea floor (17). The lashing has a balancing weight (16) that reduces the effects of waves. The placing of the balancing weight depends on the depth of the sea and the anticipated wave height.

An off-shore wind farm could be a combination of a predetermined number of VWT-2126s that are fastened to sea floor and those that are floating on the surface and are fixed with a lashing to the bottom.